This study analyzes students’ use of ChatGPT prompts to explore its potential as a supplementary feedback tool in English writing classes. Thirty-one pre-service teachers participated and were divided into high, middle, and low groups based on their self-evaluation, standardized test scores, and essay scores prior to receiving ChatGPT feedback. The data sources included their two essays, ChatGPT prompts, questionnaires, and transcripts from the second writing conference. The ChatGPT prompts and questionnaires were analyzed using descriptive statistics, and the writing conference transcripts were examined to understand the participants’ use of prompts. The results showed participants used prompts 40 times in the first assignment and 175 times in the second assignment. The average prompt usage increased from 1.5 times in the first assignment to 6.7 times in the second assignment. In terms of students’ levels, the high group used more prompts (5.58 times) than the middle (5 times) and the low groups (1.75 times). Notably, students who used ChatGPT commands five times or more were mostly from the high and middle groups. Differences in prompt usage patterns were also identified, with the high and middle groups engaging in more continuous and interactive conversations with ChatGPT. Students expressed satisfaction with ChatGPT’s feedback, particularly in vocabulary selection, grammar correction, and sentence generation.